Russula orientipurpurea Wisitr., H. Lee & Y.W. Lim, 2020

Wisitrassameewong, Komsit, Park, Myung Soo, Lee, Hyun, Ghosh, Aniket, Das, Kanad, Buyck, Bart, Looney, Brian P., Cabon, Miroslav, Adamcik, Slavomir, Kim, Changmu, Kim, Chang Sun & Lim, Young Woon, 2020, Taxonomic revision of Russula subsection Amoeninae from South Korea, MycoKeys 75, pp. 1-29 : 1

Russula orientipurpurea Wisitr., H. Lee & Y.W. Lim sp. nov. Figs 3C-E , 4C, D , 6

Material examined.

Holotype. South Korea. Jullanam-do, Yeosu-si, Dolsando islands, 202 m elev., 34°35'24"N, 127°47'57"E, Komsit Wisitrassameewong, Jae Young Park, 25 July 2017, SFC20170725-37 (Holotype, SFC!).

Etymology.

' orientipurpurea ' refers to the origin of the species, East Asia, and its typical purple color of pileus.

Diagnosis.

Pileus surface with pale cream with flushed pale purple to purple stains; spores with almost complete to complete reticulum; subfusiform to fusiform hymenial cystidia.

Pileus medium-sized, 52-60 mm diam., plano-convex to applanate with the deeply depressed center, margin inconspicuously striate up to 2 mm, acute, even; surface smooth, pruinose, slightly waxy, matt, slightly viscid when wet, cuticle peeling 1/2 to 3/4 of the pileus radius, color pale cream to cream, with darker shade of cream towards the center, typically flushed with pale or darker purple stains, sometimes with radial stripes of greyish ruby (12E5). Lamellae 4-5 mm deep, adnate, moderately distant, approximately 11-18 per cm near the pileus margin, white to pale yellow (3A3), furcations sometimes present near the stipe, lamellulae occasional, edge even. Stipe 40-50 × 11-13 mm, centrally attached, cylindrical, surface smooth, longitudinally striate, color white and sometimes with a greyish red (11D4-D5) flush; hollow. Context 2-3 mm thick at half of the pileus radius, white, rather firm but fragile in stipe when mature, turning slowly greenish with FeSO4 and pale orange to orange white with KOH; taste mild; odor slightly fruity. Spore print cream white to white.

Basidiospores (n = 80, 4, 4) (6.3-)6.9-7.3-7.8(-8.6) × (5.4-)6-6.4-6.9(-7.6) µm, subglobose to broadly ellipsoid, Q = (1.06-)1.09-1.14-1.19(-1.28), ornamentation of thin to moderately thick, 0.6-1.4 µm high ridges forming an incomplete or complete reticulum (3-7 in a 3 µm circle), in a 3 µm circle isolated warts rare (0-1 in a 3 µm circle), suprahilar spot not amyloid, small, surrounded by fine and less prominent reticulation. Basidia (28-)32-36.2-40(-45) × (7.5-)9.5-10.9-12.5(-14.5) µm, 4-spored, clavate. Basidiola (27.8-)33.4-37.7-42.1(-43.4) × (9-)9.7-10.5-11.4(-12.2) µm, narrowly clavate, with guttate or granular contents. Hymenial cystidia on lamellae sides widely dispersed to dispersed, 200-700 per mm2, (64-)74.5-87.9-101(-131) × (8.5-)10.5-12.8-15(-18.5) µm, mostly fusiform or narrowly fusiform, occasionally clavate, originating from subhymenium, emergent or not beyond basidia, apically constricted but obtuse, usually with thickened walls (up to 0.8 µm), contents optically empty, negative in sulfovanillin. Lamellar edge with dispersed basidia, true gloeocystidia (with differentiated contents) absent; marginal cells very abundant, resembling terminal cells in the pileus, usually narrowly lagenifom or subfusiform, apically narrowed but obtuse (28.5-)48-67.8-88(-121) × (3-)5.5-8.2-11(-14.5) µm; shorter narrowly clavate to clavate, (10.5-)13.5-18-22.5(-27.5) × (3.5-)5-6.5-8(-10.5) µm. Pileipellis orthochromatic in Cresyl blue, sharply delimited from the underlying context, 170-240 µm thick, with a well-defined, gelatinized, 30-60 µm thick suprapellis of ascending or erect hyphal terminations forming a trichoderm, subpellis 180-250 µm thick, dense, horizontally oriented, gelatinized and branched cylindrical to inflated hyphae; acid-resistant incrustrations absent. Hyphal terminations near the pileus margin unbranched, apically often flexuous, either long and attenuated or subcylindrical, short and obtuse, the attenuated ones (39.0-)55.5-72.3-89.0(-112.0) × (2.5-)5.0-6.1-7.2(-8.5) µm, subulate or narrowly fusiform, sometimes slightly moniliform, apically subacute, thin-walled, subterminal cells shorter, cylindrical ones with terminal cells (10-)16.5-25.3-34(-57) × (3-)4-5.2-6(-7.5) µm, apically sometimes slightly constricted, apically obtuse; followed by 0-2 unbranched short, equally wide cells, sometimes originate from branched cells. Hyphal termination near the pileus center also dimorphous, the attenuated ones prevailing with terminal cells (10.5-)18.5-50.5-82.5(-104.5) × (3.5-)4.5-6.0-7.5(-10) µm, subulate, thin-walled, apically subacute, cylindrical ones with terminal cells (13.5-)19-42.9-66.5(-85.5) × (3.5-)4.5-5.6-6.5(-9.0) µm. Pileocystidia absent. Cystidioid or oleipherous hyphae in subpellis or context absent.

Ecology.

solitary to scattered on soil in mixed forest with Quercus and Pinus trees.

Studied materials.

South Korea. Chungcheongnam-do, Gongju-si, Mt. Museong, 341 m elev., 36°35'52"N, 127°01'59"E, Hyun Lee, Seung-Yoon Oh, 26 July 2012, SFC20120726-37 (Paratype SFC!); Incheon-si, Gangwha-gun, Mt. Goryeo, 228 m elev., 37°44'54"N, 126°26'01"E, Young Woon Lim, 4 August 2012, SFC20120804-09 (Paratype, SFC!); Seoul, Gwanak-gu, Mt. Gwanak, 154 m elev., 37°27'06"N, 126°56'34"E, Hyun Lee, Won Ju Kim, 25 August 2012, SFC20120825-02 (Paratype SFC!); ibid, 202 m elev., 37°27'34"N, 126°56'19"E, Hyun Lee, Myung Soo Park, 31 August 2012, SFC20120831-04 (Paratype SFC!); ibid, 238 m elev., 37°26'53"N, 126°54'11"E, Hyun Lee, Komsit Wisitrassameewong, 19 August 2017, SFC20170819-08 (Paratype SFC!); Gyeongsangnam-do, Hapcheon-gun, Mt. Gaya, 631 m elev., 35°47'59"N, 128°05'46"E, Jae Young Park, Komsit Wisitrassameewong, Ki Hyeong Park, 26 July 2017, SFC20170726-47 (Paratype SFC!); Gyeongsangbuk-do, Ulleung-gun, Nari basin, 395 m elev., 37°31'03"N, 130°52'11"E, Jae Young Park, Nam Kyu Kim, 21 August 2017, SFC20170821-22b (Paratype SFC!).

Comments.

Russula orientipurpurea is common in mixed forests in South Korea. This species was misidentified as the North American R. mariae ( Park et al. 2013). The spores in R. orientipurpurea have more complete ridge connections (3-7 lines in the 3 µm circle) and a smaller number of warts (0-1 warts in the 3 µm circle) than those in R. mariae (lines 1-4, warts 4-6). Russula orientipurpurea is morphologically similar to R. intervenosa . However, the dark red pileus centere, broader hymenial cystidia (up to 18 µm), and the thicker pileipellis (250-600 µm) of R. intervenosa ( Crous et al. 2016) distinguishes this species from R. orientipurpurea (see Table 2 ).

Figures

Figure 3. Basidiomes of Korean Amoeninae from this study. A, B Russula bella (A-SFC 20170802 - 03, B-SFC 20170819 - 05) C-E R. orientipurpurea (SFC 20170819 - 08) F, G Russula sp. (SFC 20160726 - 13). Scale bars: 20 mm.

Figure 4. Basidiospores with scanning electron microscopy images (A, C, E) and drawing images (B, D, F) A, B Russula bella (SFC 20170819 - 05) C, D R. orientipurpurea; (SFC 20170821 - 22 b) E, F Russula sp. (SFC 20160726 - 13). Scale bars: 2 µm.

Figure 6. Microscopic features of Russula orientipurpurea (SFC 20170725 - 37) A basidia B basidiola C clavate marginal cells D hymenial cystidia on lamellae sides E subulate marginal cells F hyphal termination at pileus margin G hyphal termination at pileus centre. Scale bars: 10 µm.